VI PREFAi 



an appointment as scientific aid in the United States Department of 

 ulture, was engaged al Berlin in a revision of the Leguminosae 

 of Porto Rico. The revision was based upon a stud> of collections 

 an<l literature, unaccompanied l»v field work in the island. It was 

 originally in tended to publish the results of this work conjointly with 

 an account of the agricultural relations of the leguminous plants of 

 thai island, )>ut as it proved to be necessary to postpone the prepare 

 tion of this latter paper foi more detailed investigation Miss Perkins's 

 paper is now presented separately for publication. This paper differs 

 in several respects from the systematic treatment of leguminous 

 plants presented in other numbers of these Contributions, and such 

 differences must be taken only as an expression of the yiews of the 

 author. 



The fifth paper i- a " Report on the Diatoms of the Albatross \ 

 ages in the Pacific ( >cean, 1888 L904,' 1 hy Dr. Albert Mann, assisted in 

 the bibliography and citations by P. L. Kicker. In the autumn of 

 L887 the steamer Albatross, of the United States Bureau of Fisheries, 

 which had previously been employed on the Atlantic coast of North 

 America, was dispatched to the Pacific ( >cean, where it has -nice been 

 iged in fishery and deep-sea investigations on the western coast of 

 the United State-, off British Columbia and Alaska, and also in more 

 distant regions. The bottom samples obtained l>y the dredge and 

 sounding cup during the several cruises from L888 to L904, inclusive, 

 were referred to Doctor Mann, an expert student of I ho diatoms. He 

 has separated and reported on these minute plant organisms, a difficult 

 and painstaking task, the results of which are given in the paper pre- 

 sented herewith. With very few exceptions the titles in the bibli- 

 ography and the citations throughout the body of the report have been 

 verified by Mr. P. L. Kicker, to whom acknowledgment is here made. 



The sixth paperis entitled ••'The Cyperaceae of Costa Rica," by 

 C. B. Clarke. Several years ago Prof. Henri Pittier, while actively 

 engaged in studying the plants of ( losta Rica, invited Mr. ( J. B. ( Jlarke, 

 of the Kew Herbarium, then the greatest living authority on the 

 Cyperaceae, to prepares synopsis of the genera and species of that 

 family found in Costa Rica. This work was gladly undertaken by 

 Mr. Clarke. Soon after the synopsis was submitted Professor Pittier 

 left Costa Rica to accept a position in the Department of Agriculture, 

 in Washington, and after his arrival offered the paper to the Tinted 

 States National Museum for publication. Mr. Clarke having died in 

 the meantime, it seemed desirable to publish it with as little change a> 

 possible. As it was prepared in Latin, however, the Advisory Com- 

 mittee on Publications recommended that it should be translated into 

 English, and Dr. E. L Greene was asked to prepare the manuscript. 

 In performing this task Doctor Greene has followed as closely as possi- 

 ble the term- and phrasing of Mr. Clarke's papers written in English. 



